This article proposes a novel Airborne Internet of Things Network (AIN) system architecture for monitoring water quality, combining existing wireless technologies with the aid of a low altitude platform (LAP) to relay data over long distances in hilly terrain. The proposed system consists of water quality sensors, smart utility network (SUN) devices, long range (LoRa) wireless devices, an LAP air balloon, and Wi-Fi devices. A measurement campaign was conducted to assess the proposed system, focusing on the communication link reliability and the LAP stability and robustness. Several constraints, such as payload limit and safe weather conditions, were also highlighted for operating the LAP with extensive and reliable coverage. On the other hand, characterizing the wireless channel has become a crucial parameter for planning and deploying Internet of Things (IoT) applications. Accordingly, this work proposes a novel hybrid machine learning (ML)-based semi-empirical path loss (PL) model for LoRa wireless communication. The results validated the proposed system’s effectiveness, unique characteristics, and capability to monitor water quality in a harsh environment. Results also revealed a significant difference in packet delivery rate (PDR) for different gateway height and spreading factor (SF) configurations. For instance, switching SF7 to SF12 increased PDR by 28.7%. Meanwhile, increasing gateway height increased PDR by 29.2% for similar SF configurations. The evaluation also revealed that none of the established PL models are suitable to represent harsh tropical environments. Finally, the proposed model achieved nearly 90% prediction accuracy for testing samples and 95% accuracy for training and overall measurement samples, vastly outperforming conventional models.

IEEE P1900.4 is an emerging standard for optimized radio resource utilization where cognitive radio technologies are used for efficient spectrum utilization. In this paper, we design and implement a cognitive wireless network system based on open documents of IEEE P1900.4, and evaluate its performance using UDP streaming and HTTP download. Our experiments show interesting results that total network throughput in the HDP streaming is improved by 30% although some of individual terminals can not necessarily obtain better throughput. Also, it is shown that performance in the HTTP download becomes worse by up to about 40% as the number of handover increases due to the TCP window control. Our analysis is expected to point out importance of higher layer coordination with lower layers for end-to-end performance improvements in cognitive wireless networks.

Multipath TCP (MPTCP), which enables the use of multiple wireless links (e.g., Wi-Fi and LTE) for data transmissions, is an excellent technology for evolving multi-homing devices in mobile wireless networks. This paper explores concepts and feasibility of realizing MPTCP with path awareness (PA), in which the path-aware information is leveraged to reinforce the MPTCP transmissions. In particular, when aware of a network situation, a device can facilitate a mechanism that dynamically shifts the MPTCP traffic to a single path and vice versa. As a result, MPTCP with PA could solve the significant problem of negative aggregation benefit when the MPTCP throughput over divergent paths is worse than the best one of single-path TCP. We illustrate the feasibility of the proposed concept through our new implementation of a so-called MPTCP-LA (i.e., MPTCP with Loss Awareness). MPTCP-LA keeps the aggregation benefits non-negative by temporarily switching an MPTCP transmission on a path to a standby condition when the on-device observed loss reaches a threshold. We extensively evaluate MPTCP-LA in comparison to the standard MPTCP in an emulated environment. The results show that MPTCP-LA has better performance regarding enhancing throughput and saving networking resources.

The IEEE 802.11ad technology, which allows wireless devices to communicate in the unlicensed 60 GHz ISM band, promisingly provides multi-Gbps data rates for bandwidth-intensive applications. After years of research and development, we are now observing an increasing number of commodity IEEE 802.11ad radios that motivate researchers to exploit the IEEE 801.11ad capability for applications. This work first conducts an empirical study on the IEEE 802.11ad performance. In particular, we characterize the performance of IEEE 802.11ad links considering the variation of network parameters and interference. Secondly, we investigate the possibility of introducing IEEE 802.11ad to an evolving Wi-Fi network. The evaluation results show that our off-the-shelf IEEE 802.11ad hardware can achieve the Gbps level throughput of the transmission control protocol (TCP) and user datagram protocol (UDP). However, the evolvement is not trivial since the hardware can not well maintain the 60 GHz link. The main reason is lacking the fast switchover function between an IEEE 802.11ad and a legacy Wi-Fi link. We then seek the potential of multipath TCP (MPTCP) for the expected switchover. The default MPTCP, which enables data transmissions on both the IEEE 802.11ad and Wi-Fi links, is harmful to the IEEE 802.11ad throughput. Meanwhile, the backup mode of MPTCP, in which the Wi-Fi link acts as a backup for IEEE 802.11ad one, can maintain the comparable performance. Therefore, we propose to adopt MPTCP with the backup mode in the evolving Wi-Fi networks. The efficiency of MPTCP-based switchover is confirmed by conducting real experiments.

New services on trains are attracting a great deal of attention throughout Europe and Asia where trains are one of the most important forms of transportation. We introduced two information services on bullet-trains; Internet access and video. There are three technical challenges posed by seamless handover at 300 hn/h, aggregation of multiple access, and attack-tolerant communications. We proposed a network architecture to solve them based on the requirements of these services. Due to its extendibility and flexibility, new services that will be introduced in the future can be integrated easily. We are currently developing a tested for experimental evaluations.